Sound generator

ABSTRACT

A compact sound generator which includes an insulating supporting base having an integrally formed bobbin, a passage extending through the bobbin and the support for accommodating therein a reciprocating plunger, an electrical winding on the bobbin which actuates the plunger upon energization, and a resilient sound-generating diaphragm strip mounted at opposite ends to the support with the unsupported intermediate span engageable by the plunger to generate the sound.

United States Patent [72] Inventor Rein ll-hus Long Branch, NJ. [21] App]. No. 880,135 [22] Filed Nov. 26, 1969 [45] Patented Dec. 28, 1971 [73] Assignee Wheelock Signals, Inc.

Long Branch, NJ.

[54] SOUND GENERATOR 11 Claims, 4 Drawing Figs.

[52] U.S. Cl 340/388 [51] Int. Cl G08!) 3/00 [50] Field of Search 340/388 [56] Reierences Cited UNITED STATES PATENTS 2,227,289 12/1940 White et a1. 340/388 3,408,645 10/1968 Doggart et a1. 340/388 Primary Examiner-Richard Murray Attorney-Brumbaugh, Graves, Donohue & Raymond ABSTRACT: A compact sound generator which includes an insulating supporting base having an integrally formed bobbin, a passage extending throughthe bobbin and the support for accommodating therein a reciprocating plunger, an electrical winding on the bobbin which actuates the plunger upon energization, and a resilient sound-generating diaphragm strip mounted at opposite ends to the support with the unsupported intermediate span engageable by the plunger to generate the sound.

SOUND GENERATOR This invention relates to sound generators and more particularly to a novel, compact sound generator of novel design.

The sound generator of the present invention embodies a support base on which a bobbin is integrally formed, a passage through the support base and the bobbin to receive a reciprocating plunger, an electrical winding on the bobbin which upon energization actuates the plunger, and a resilient sound-generating diaphragm strip mounted at opposite ends to the support base with the unsupported intermediate span engageable by the plunger.

Other features of the sound generator of the present invention include adjustable means carried by the support which engages a span of the diaphragm for varying the frequency and amplitude of vibration, a U-shaped return yoke to provide a return path for the magnetic flux developed in the plunger upon energization of the winding, means for slidably receiving the magnetic flux return element in the support base, means within the bobbin for accommodating a spring in constant engagement with the plunger through which the plunger is connected in series with the electrical winding, and a snap-locking cover for the base which facilitates mounting of the sound generator.

For a complete understanding of the present invention reference should be made to the detailed description which follows and to the accompanying drawings in which:

FIG. 1 is a plan view of the sound generator of the present invention with the cover partially broken away;

FIGS. 2 and 3 are cross-sectional views taken along the lines 22 and 3-3, respectively, of FIG. 1, looking in the direction of the arrows; and

H6. 4 is a bottom view of the sound generator.

The sound generator of the present invention includes a support base 10 made of insulating material, preferably an insulating plastic material, a bobbin l1 integrally formed on and upstanding from the center of the support, a passage 12 extending through the bobbin and the support, a reciprocating plunger 13 accommodated within said passage, an electrical winding 14 on the bobbin and energizable to actuate the plunger, and a resilient sound-generating diaphragm strip 15 mounted at opposite ends to the support with the unsupported intermediate span engageable by the lower end of the plunger.

The support base 10, as viewed in FIG. 1, is generally rectangular in shape and has a pair of terminals 16, 17 mounted to the top of the base, one on each side of the upstanding bobbin 11. The terminal 16 is mounted in place by an electrically conductive screw 18 locked in place by an electri-. cally conductive nut 19. The electrically conductive screw 18 serves not only as a mounting for the terminal 16 but also as a mounting for one end of the diaphragm l and as an electrical connection between the terminal 16 and the diaphragm 15.

The terminal 17 is mounted to the supporting base by a screw 20 and a locking nut 21. The terminal 17 has a threaded opening which receives a screw 22 made of insulating material. The lower end of the screw engages the diaphragm 15. A spring 23 is accommodated on the screw intermediate the screwhead and the supporting base. The screw provides an adjustable means for exerting a variable force on the diaphragm to vary the frequency and amplitude of vibration of the diaphragm.

The support base 10 has a pair of depending legs 24 and 25 at one end and a continuous depending leg 26 at the other end. As best shown in FIG. 2, one extended end of the diaphragm is accommodated between the depending legs 24 and 25 and the other extended end of the diaphragm is accommodated within a slot 27 of the depending leg 26.

The diaphragm 15 is made of a resilient conducting metal, for example a steel or aluminum sheet of approximately 0.006 to 0.008 inch thickness, having a bend line (not shown) intermediate the screw 18 and the plunger 13 so that the tendency is for the right end, as viewed in FIG. 2, to be higher than the left end, with the result that the right end is biased upwardly when it is mounted as shown in FIG. 2. The center of the diaphragm 15 carries a contact 28, preferably made of silvercadmium oxide, which is engageable with the lower end of the plunger 13.

The particular design and mounting of the diaphragm 15 provides greater impact energies and thus increased sound generation produced by the impact of the reciprocating plunger 13. The plunger 13 contains an enlarged lower head l3which carries a contact 29, preferably also silver-cadmium oxide, which engages the diaphragm contact 28.

A magnetic flux conducting yoke 30 made of paramagnetic material preferably steel, is slidably received by the support base 10' and it provides a return path for the magnetic flux developed in the plunger upon energization of the coil. The yoke 30 has an upper arm 31 and a lower arm 32. The upper arm is accommodated in an open ended recess 33 formed in the upper end of the bobbin 11. When accommodated in the open ended recess, the arm 3] rests upon a shoulder 34. The lower arm 32 of the yoke passes through a slot 35 in the support base and it has an annular opening 36 therein so that when properly positioned on the support base the opening 36 is aligned with the plunger 13 and the arm does not interfere with the reciprocation of the plunger.

The upper end of the bobbin has another open ended recess 37 (see FIG. 2) which accommodates one end of an L-shaped leaf-type spring contact 38. The spring contact 38 is afiixed to the yoke 30 by a screw 39.

The winding 14, the magnetic flux return yoke 30 and the contact 38 are enclosed within a cover 40, preferably made of insulating plastic material, which snap locks onto the support base 10. The cover 40 has internal shoulders 41 which are adapted to seat against the upper surface of the support base. Also, the front and rear walls of the cover have integrally formed thereon small projections 42 which interlock with the lower edges of the support base.

The cover 40 has cutout portions 43 through which the terminals l6 and 17 extend to be accessible, an opening 44 in the top which makes it possible to adjust the screw 22 without removing the cover, and integral bosses 45 which permit the sound generator assembly to be mounted to another surface.

The diaphragm 15, the plunger 13, the contact 38 and the winding 14 are electrically connected in series so that when the plunger 13 is in its lowermost position and the contacts 28 and 29 are closed the application of an electrical potential across the terminals 16 and 17 will complete a circuit to energize the winding 14 through the diaphragm, the plunger and the contact 38. This electrical circuit is broken by the upward displacement of the plunger, permitting the plunger to drop back into engagement with the diaphragm. Since the contact 38 remains in engagement with the upper end of the plunger, the recess in which it is accommodated must be deep enough to permit the free end of the contact 38 to move with the reciprocation of the plunger.

The invention has been shown and described in single preferred form and by way of example only, and obviously many modifications and variations are possible within the spirit of the invention. For example, the electrically conductive screw 18 and nut 19 can be modified to include other conductive fasteners such as eyelets and rivets. Similarly, other types of fasteners (not necessarily metallic or conductive) can be substituted for the screw 20 and locking nut 21, and other electrically conductive fastening devices, such as eyelets, rivets or welding, can be substituted for the screw 39. The invent'ion should not be limited, therefore, to any particular form or embodiment except insofar as such particular form or embodiment is expressly set forth in the claims I claim:

1. A sound generator comprising a support base, a resilient sound-generating diaphragm strip mounted at opposite ends to the support with an unsupported intermediate span, a bobbin integrally forrned on the support, a passage through the bobbin and the support, a plunger accommodated within said passage and free to reciprocate within the passage and to thereby engage and disengage the unsupported span of the diaphragm, and an electrical winding on the bobbin energizable to actuate the plunger and cause it to reciprocate.

2. A sound generator as set forth in claim ll in which the diaphragm is connected in series with the plunger to complete the electrical circuit to energize the winding when the plunger engages the diaphragrn and including a spring contact in constant engagement with the end of the plunger opposite the end which engages the diaphragm and connected in series with the plunger and the diaphragm to energize the winding.

3. A sound generator as set forth in claim 1 including adjustable means carried by the support and engageable with a span of the diaphragm intermediate the plunger and a mounted end of the diaphragm for exerting a variable force on the diaphragm to vary the frequency and amplitude of vibration of the diaphragm.

4. A sound generator as set forth in claim 1 in which said adjustable means is an adjustable threaded screw having one end engageable with said diaphragm.

5. A sound generator as set forth in claim 1 including a mag netic flux return yoke having a pair of arms and means formed in the support for slidable receiving the yoke so that the arms of the yoke are located at opposite ends of said passage.

6. A sound generator as set forth in claim 1 in which said means formed in the support for slidably receiving the arms of the magnetic flux return yoke includes an open-ended recess formed in the end of the bobbin for receiving one of the arms, .a shoulder within said recess against which one of the arms of the magnetic flux return yoke slidably engages, and a guide slot spaced apart from said shoulder for slidably receiving the other arm of said magnetic flux return yoke.

7. A sound generator as set forth in claim 1 in which one of the arms of the magnetic flux yoke has an opening therein to receive the plunger and permit it to reciprocate freely.

8. A sound generator as set forth in claim 1 including a leaftype contact spring in constant engagement with the end of the plunger opposite the end which engages the diaphragm and connected in series with the plunger and the diaphragm to energize the winding and a recess formed in the end of the bobbin for accommodating the leaf-type contact spring inter mediate the plunger and one of the arms of the yoke to enable the leaf contact spring to maintain contact with the plunger.

9. A sound generator as set forth in claim 1 in which said support includes an extended base on which the bobbin upstands at the center and depending legs at opposite ends of said base, and including terminals mounted on said base on opposite sides of said bobbin, an electrically conductive mounting which serves both as a mounting for one end of the diaphragm and as an electrical connection between a terminal and the diaphragm and a slot formed in the opposite leg of the base for receiving the opposite end of the diaphragm.

10. A sound generator as set forth in claim 1 including a cover snap locking with said base and having integrally formed bosses thereon for mounting the sound generator.

11. A sound generator as set forth in claim 1 wherein the support base is made of insulating material.

5% UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTION Patent, 3,631,481 Dated December 28, 1971 Inventor(s) Rein Haus It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

* Column 2, line 7, "13" should read --l3a-. Column 3, line 1,

Column 3,

the claim reference numeral "11" should read --l line 19, "slidable" should read -s1idab1y-.

Signed and sealed this 6th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. A sound generator comprising a support base, a resilient sound-generating diaphragm strip mounted at opposite ends to the support with an unsupported intermediate span, a bobbin integrally formed on the support, a passage through the bobbin and the support, a plunger accommodated within said passage and free to reciprocate within the passage and to thereby engage and disengage the unsupported span of the diaphragm, and an electrical winding on the bobbin energizable to actuate the plunger and cause it to reciprocate.
 2. A sound generator as set forth in claim 11 in which the diaphragm is connected in series with the plunger to complete the electrical circuit to energize the winding when the plunger engages the diaphragm, and including a spring contact in constant engagement with the end of the plunger opposite the end which engages the diaphragm and connected in series with the plunger and the diaphragm to energize the winding.
 3. A sound generator as set forth in claim 1 including adjustable means carried by the support and engageable with a span of the diaphragm intermediate the plunger and a mounted end of the diaphragm for exerting a variable force on the diaphragm to vary the frequency and amplitude of vibration of the diaphragm.
 4. A sound generator as set forth in claim 1 in which said adjustable means is an adjustable threaded screw having one end engageable with said diaphragm.
 5. A sound generator as set forth in claim 1 including a magnetic flux return yoke having a pair of arms and means formed in the support for slidable receiving the yoke so that the arms of the yoke are located at opposite ends of said passage.
 6. A sound generator as set forth in claim 1 in which said means formed in the support for slidably receiving the arms of the magnetic flux return yoke includes an open-ended recess formed in the end of the bobbin for receiving one of the arms, a shoulder within said recess against which one of the arms of the magnetic flux return yoke slidably engages, and a guide slot spaced apart from said shoulder for slidably receiving the other arm of said magnetic flux return yoke.
 7. A sound generator as set forth in claim 1 in which one of the arms of the magnetic flux yoke has an opening therein to receive the plunger and permit it to reciprocate freely.
 8. A sound generator as set forth in claim 1 including a leaf-type contact spring in constant engagement with the end of the plunger opposite the end which engages the diaphragm and connected in series with the plunger and the diaphragm to energize the winding and a recess formed in the end of the bobbin for accommodating the leaf-type contact spring intermediate the plunger and one of the arms of the yoke to enable the leaf contact spring to maintain contact with the plunger.
 9. A sound generator as set forth in claim 1 in which said support includes an extended base on which the bobbin upstands at the center and depending legs at opposite ends of said base, and including terminals mounted on said base on opposite sides of said bobbin, an electrically conductive mounting which serves both as a mounting for one end of the diaphragm and as an electrical connection between a terminal and the diaphragm and a slot formed in the opposite leg of the base for receiving the opposite end of the diaphragm.
 10. A sound generator as set forth in claim 1 including a cover snap locking with said base and having integrally formed bosses thereon for mounting the sound generator.
 11. A sound generator as set forth in claim 1 wherein the support base is made of insulating material. 